U.S. patent number 8,364,351 [Application Number 12/996,442] was granted by the patent office on 2013-01-29 for occupant protection device.
This patent grant is currently assigned to Toyota Jidosha Kabushiki Kaisha. The grantee listed for this patent is Syuzo Hashimoto. Invention is credited to Syuzo Hashimoto.
United States Patent |
8,364,351 |
Hashimoto |
January 29, 2013 |
Occupant protection device
Abstract
An occupant protection device includes: a collision prediction
part; a seatback actuator that adjusts a reclining angle; a
seatbelt retracting part; a reclining angle sensor; and a
controller that sets the reclining angle to a target angle and that
controls the seatbelt retracting part so that the seatbelt is
retracted when the collision prediction part determines that a
collision will occur. Accordingly, the controller executes a
control so that the driving force of seatbelt retracting part when
the reclining angle is decreased is smaller than at least one of
the driving force of seatbelt retracting part when the reclining
angle is not changed or when the driving force of seatbelt
retracting part when the reclining angle is increased.
Inventors: |
Hashimoto; Syuzo (Toyota,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hashimoto; Syuzo |
Toyota |
N/A |
JP |
|
|
Assignee: |
Toyota Jidosha Kabushiki Kaisha
(Toyota-shi, Aichi-ken, JP)
|
Family
ID: |
41417181 |
Appl.
No.: |
12/996,442 |
Filed: |
June 8, 2009 |
PCT
Filed: |
June 08, 2009 |
PCT No.: |
PCT/IB2009/005880 |
371(c)(1),(2),(4) Date: |
December 06, 2010 |
PCT
Pub. No.: |
WO2009/150511 |
PCT
Pub. Date: |
December 17, 2009 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
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US 20110074190 A1 |
Mar 31, 2011 |
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Foreign Application Priority Data
|
|
|
|
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Jun 9, 2008 [JP] |
|
|
2008-150380 |
|
Current U.S.
Class: |
701/45; 180/271;
701/301; 297/216.1 |
Current CPC
Class: |
B60N
2/22 (20130101); B60R 22/46 (20130101); B60N
2/0276 (20130101); B60R 21/0136 (20130101); B60R
2021/01272 (20130101) |
Current International
Class: |
B60R
22/00 (20060101) |
Field of
Search: |
;701/45,301 ;180/271
;280/734 ;340/436 ;297/216.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1 591 308 |
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Nov 2005 |
|
EP |
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11-334437 |
|
Dec 1999 |
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JP |
|
2001-322532 |
|
Nov 2001 |
|
JP |
|
2003-165406 |
|
Jun 2003 |
|
JP |
|
2005-238934 |
|
Sep 2005 |
|
JP |
|
2005-306340 |
|
Nov 2005 |
|
JP |
|
2006-82703 |
|
Mar 2006 |
|
JP |
|
2007-106355 |
|
Apr 2007 |
|
JP |
|
WO 01/45985 |
|
Jun 2001 |
|
WO |
|
WO 2006/134417 |
|
Dec 2006 |
|
WO |
|
Other References
International Search Report in International Application No.
PCT/IB2009/005880; Mailing Date: Jun. 1, 2010. cited by applicant
.
Written Opinion of the International Searching Authority in
International Application No. PCT/IB2009/005880; Mailing Date: Jun.
1, 2010. cited by applicant .
Notification of Reason(s) for Refusal in JP 2008-150380; Drafting
Date: Apr. 27, 2010. cited by applicant.
|
Primary Examiner: Algahaim; Helal A
Attorney, Agent or Firm: Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP
Claims
The invention claimed is:
1. An occupant protection device comprising: a collision prediction
part that predicts whether a collision will occur for a host
vehicle; a seatback actuator that adjusts a reclining angle of a
seatback that is defined as an angle between the seatback and a
seat cushion; a seatbelt retracting part that exerts a driving
force to retract a seatbelt to restrain the occupant; a reclining
angle sensor that detects the seatback reclining angle; and a
controller that controls the seatback actuator so that the
reclining angle becomes a target reclining angle and that controls
the seatbelt retracting part to retract the seatbelt if the
collision prediction part determines that the collision will occur,
wherein the controller executes a control, so that the driving
force of the seatbelt retracting part when the reclining angle of
the seatback is decreased is smaller than at least one of the
driving force of the seatbelt retracting part in retracting the
seatbelt when the reclining angle of the seatback is not changed
and the driving force of the seatbelt retracting part when the
reclining angle of the seatback is increased.
2. The occupant protection device according to claim 1, wherein the
seatbelt retracting part includes a motor, and the controller
reduces the driving force of the seatbelt retracting part by
reducing an electric current supplied to the motor.
3. The occupant protection device according to claim 1, wherein the
controller prohibits the seatbelt retracting part from retracting
the seatbelt if the seatback reclining angle is equal to or exceeds
a threshold reclining angle.
4. The occupant protection device according to claim 1, wherein the
controller determines whether the seatback reclining angle detected
by the reclining angle sensor is the target reclining angle.
5. The occupant protection device according to claim 4, wherein the
controller drives the seatback actuator to decrease the reclining
angle of the seatback if the controller determines that the
detected reclining angle of the seatback exceeds the target
reclining angle.
6. The occupant protection device according to claim 4, wherein the
controller drives only the seatbelt retracting part from among the
seatback actuator and the seatbelt retracting part if the
controller determines that the detected reclining angle of the
seatback is the target reclining angle.
7. The occupant protection device according to claim 1, wherein if
the collision prediction part determines that the collision will
occur and the seatback actuator is controlled by the controller to
adjust the seatback reclining angle to become the target reclining
angle, the controller determines whether a prescribed period of
time has elapsed after the control of the seatback is started; if
the controller determines that the prescribed period of time has
elapsed, the controller stops driving the seatback actuator.
8. The occupant protection device according to claim 1, further
comprising: a collision detection sensor, wherein: the collision
prediction part calculates an estimated time of impact which is an
estimated amount of time before the host vehicle will collide with
an object; and after the collision prediction part predicts that a
collision will occur and the controller controls the seatback
actuator to adjust the reclining angle to become the target
reclining angle from an initial reclining angle, if the collision
detection sensor does not detect a collision by the estimated time
of impact, the controller controls the seatback actuator to stop
the seatback actuator or to return the seatback to the initial
reclining angle.
9. The occupant protection device according to claim 1, wherein the
controller executes a control, so that the driving force of the
seatbelt retracting part when the reclining angle of the seatback
is increased is larger than at least one of the driving force of
the seatbelt retracting part in retracting the seatbelt when the
reclining angle of the seatback is not changed and the driving
force of the seatbelt retracting part when the reclining angle of
the seatback is decreased.
10. The occupant protection device according to claim 9, wherein
the driving force of the seatback actuator when the reclining angle
of the seatback is increased is set smaller than the driving force
of the seatback actuator when the reclining angle of the seatback
is decreased.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a national phase application of International
Application No. PCT/IB2009/005880, filed Jun. 8, 2009, and claims
the priority of Japanese Application No. 2008-150380, filed Jun. 9,
2008, the contents of both of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an occupant protection device, and
particularly to an occupant protection device that predicts a
collision to protect an occupant.
2. Description of the Related Art
Various arts are proposed as an occupant protection device that
protects an occupant in the event of a collision. For example,
related arts include: occupant protection devices that protect an
occupant by suitably adjusting the posture of an occupant by
tilting a seatback forward if the seatback is reclined in an
collision prediction state; and an occupant protection device that
protects an occupant by retracting a seatbelt in an collision
prediction state.
The occupant protection device of this type has been described in
Japanese Patent Application Publication No. 11-334437
(JP-A-11-334437), for example. In the art disclosed in
JP-A-11-334437, the occupant protection device determines that a
collision is imminent, and inclines the seatback forward to a
prescribed position if the seatback is reclined beyond a prescribed
range, and then retracts a seatbelt by operating a
pre-tensioner.
However, in the art disclosed in JP-A-11-334437, the seatbelt is
retracted after the operation of the seatback. Preferably, for a
quicker operation of occupant protection, the inclination of the
seatback and the retraction of the seatbelt are performed
simultaneously. In the above art, electric power needed to operate
the operation of the occupant protection devices increase.
Therefore, control on the occupant protection device has room for
improvement.
SUMMARY OF THE INVENTION
The present invention provides an occupant protection device that
inclines the seatback of a vehicle seat and retracts a seatbelt
with suppressing power consumption.
The occupant protection device according to an aspect of the
present invention includes: a collision prediction part that
predicts whether a collision will occur for a host vehicle; a
seatback actuator that adjusts a reclining angle of the seatback
that is defined as a angle between the seatback and a seat cushion;
a seatbelt retracting part that exerts a driving force to retract a
seatbelt to restrain the occupant; a reclining angle sensor that
detects the reclining angle; and a controller that controls the
seatback actuator so that the reclining angle becomes a target
angle and that controls the seatbelt retracting part to retract the
seatbelt, if the it is determined that the collision will occur.
The controller executes a control, so that the driving force of the
seatbelt retracting part when the reclining angle of the seatback
is decreased is smaller than at least one of the driving force of
the seatbelt retracting part in retracting the seatbelt when the
reclining angle of the seatback is not changed and the driving
force of the seatbelt retracting part when the reclining angle of
the seatback is increased.
According to the above aspect, the collision prediction part
predicts a collision will occur for the host vehicle. For example,
the prediction of a collision of the host vehicle is made possible
by detection of a distance between the host vehicle and the object
and by calculation of an estimated time of impact between the host
vehicle and the object.
A reclining angle of the seatback that is a angle between the
seatback and the seat cushion is changed by the drive of the
seatback actuator, and the seatbelt that restrains the occupant is
retracted by the drive of the seatbelt retracting part. The
reclining angle of the seatback is detected by the reclining angle
sensor.
When a collision is predicted by the collision prediction part, the
controller controls the seatback actuator to change the reclining
angle of the seatback to become the target angle, and also controls
the seatbelt retracting part to retract the seatbelt. That is, the
reclining angle of the seatback can suitably be adjusted, and
restraining strength of the seatbelt can suitably be adjusted. Thus
the occupant can be protected in the collision.
When the collision is predicted, the controller executes the
control, so that the driving force of the seatbelt retracting part
when the reclining angle of the seatback is decreased is smaller
than at least one of the driving force of the seatbelt retracting
part in retracting the seatbelt when the reclining angle of the
seatback is not changed and the driving force of the seatbelt
retracting part when the reclining angle of the seatback is
increased. That is, when the operation of inclining the seatback
frontward and the operation of retracting the seatbelt are
performed at the same time upon the prediction of a collision, the
occupant is restrained by both of these operations at the same
time. For this reason, an appropriate restraining force of the
seatbelt can easily be achieved when an occupant is restrained by
the seatbelt. Thus, driving force in retracting the seatbelt is
reduced. Reduction of the driving force of the seatbelt retracting
part in the manner described above enables the seatbelt retracting
part to reduce its power consumption. Thus, the inclining operation
of the seatback and the retraction of the seatbelt are suitably
performed, and the power consumption is suppressed.
In the above aspect, the seatbelt retracting part may include a
motor, and the controller may reduce the driving force of the
seatbelt retracting part by reducing an electric current supplied
to the motor.
In the above aspect, the controller may prohibit the seatbelt
retracting part from retracting the seatbelt if the reclining angle
is equal to or exceeds a threshold reclining angle. That is, if the
seatback is reclined rearward at the threshold reclining angle or
more, posture of the occupant can suitably be adjusted, and the
operating electric power of the seatback actuator is sufficiently
maintained, by prohibiting the retraction of the seatbelt.
As described above, according to an aspect of the present
invention, if the seatback is inclined to the target reclining
angle and the seatbelt is retracted in the collision prediction
state, the controller executes the control, so that the driving
force in retracting the seatbelt when the reclining angle of the
seatback is decreased is smaller than at least one of the driving
force in retracting the seatbelt when the reclining angle of the
seatback is not changed and the driving force when the reclining
angle of the seatback is increased. Thus, power consumption
necessary for retracting the seatbelt can be reduced, so that the
inclination of the seatback and the retracting operation of the
seatbelt can suitably be performed, and the power consumption is
suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
The features, advantages, and technical and industrial significance
of this invention will be described in the following detailed
description of example embodiments of the invention with reference
to the accompanying drawings, in which like numerals denote like
elements, and wherein:
FIG. 1 shows the general arrangement of an occupant protection
device in a vehicle according to an aspect of the present
invention;
FIG. 2 is a block diagram that shows the configuration of the
occupant protection device according to an embodiment of the
present invention;
FIG. 3 is a diagram for explaining the adjustment of a seatback
when a collision is predicted;
FIG. 4A shows an electric current that is applied to a seat
actuator;
FIG. 4B shows an electric current that is applied to a seatbelt
motor when the seatback is reclined rearward beyond a target angle
when the collision is predicted;
FIG. 5 is a flow chart that shows an example of the process
performed in a collision determination ECU in one embodiment of the
occupant protection device;
FIG. 6 is a flow chart that shows an example of the process
performed in an occupant protection control ECU in one embodiment
of the occupant protection device;
FIG. 7 is a flow chart that shows an example of occupant protection
operation start process performed in the occupant protection
control ECU in one embodiment of the occupant protection device;
and
FIG. 8 is a flow chart that shows a modification of occupant
protection operation start process performed in the occupant
protection control ECU in one embodiment of the occupant protection
device.
DETAILED DESCRIPTION OF EMBODIMENTS
An embodiment of the present invention will be described
hereinafter in detail with reference to accompanying drawings. FIG.
1 is a drawing that shows a general arrangement of the occupant
protection device in the vehicle according to the embodiment of the
present invention, and FIG. 2 is a block diagram that shows the
configuration of the occupant protection device according to the
embodiment of the present invention.
As shown in FIG. 1 and FIG. 2, the occupant protection device 10
includes: a seat 34 that includes a seat cushion 35 and seatback
36; a seatbelt 38, a front millimeter wave radar 12 that detects
the distance to objects in front of the host vehicle; a front
lateral millimeter wave radar 14 that detects the distance to
objects in the lateral front of the host vehicle; a stereo camera
16 that captures an image of the front; a rear millimeter wave
radar 18 that detects the distance to objects behind the host
vehicle; a rear lateral millimeter wave radar 20 that detects the
distance to objects in the lateral rear of the vehicle; and a
collision determination ECU (Electronic Control Unit) 22 (collision
prediction part). These components are connected to a bus 24. The
front millimeter wave radar 12, the front lateral millimeter wave
radar 14, the stereo camera 16, the rear millimeter wave radar 18,
and the rear lateral millimeter radar 20 monitor the surroundings
of the host vehicle and output their results to the collision
determination ECU 22.
For example, the front millimeter wave radar 12 may be disposed
near the center of the front grille, and the front lateral
millimeter wave radar 14 may be disposed near the lateral side ends
of a bumper. The front millimeter wave radar 12 and the front
lateral millimeter wave radar 14 transmit millimeter waves to the
front and the lateral front of the vehicle, respectively, and
receive radio waves reflected from any objects present. The front
millimeter wave radar 12 and the front lateral millimeter wave
radar 14 then calculate the distance to the objects and the speed
relative to the host vehicle based on a traveling time of
millimeter waves, a frequency difference caused by the Doppler
effect, etc. Likewise, the rear millimeter wave radar 18 and the
rear lateral millimeter wave radar 20 may be disposed in a rear
bumper or the like, and transmit millimeter waves to the rear and
the lateral rear of the vehicle and receive radio waves reflected
from any objects present, and then calculate the distance to the
object and a relative speed of the object based on a traveling
time, a frequency difference caused by the Doppler effect, etc.
The stereo camera 16 is disposed near the center in an upper
portion of a windshield, and captures an image of the front of the
vehicle in order to detect objects around the vehicle and to
calculate the distances to the objects. However, the stereo camera
16 may be omitted from the configuration.
The collision determination ECU 22 predicts whether a collision
will occur based on obtaining detected values from the front
millimeter wave radar 12, the front lateral millimeter radar 14,
the stereo camera 16, the rear millimeter wave radar 18, and the
rear lateral millimeter radar 20. Various conventional arts can be
applied for predicting a collision. Therefore, detailed description
of the collision prediction will be omitted.
The occupant protection device 10 according to an embodiment of the
present invention is connected to the bus 24 while further
including an occupant protection control ECU 26 that controls the
state adjustment of the seatback 36 and the retraction of the
seatbelt 38 when a collision is predicted by the collision
determination ECU 22.
The occupant protection control ECU 26 is connected with a seatback
angle detection sensor 30 that detects the reclining angle of the
seatback 36 with respect to the seat cushion 35 (an angle between
the seatback 36 and the seat cushion 35), and a seat actuator 28 (a
seatback actuator that adjusts the reclining angle of the seatback
36. When a the collision determination ECU 22 determines that a
collision is imminent, the occupant protection control ECU 26
controls the seat actuator 28 to actuate a seat reclining mechanism
(not shown) so that the reclining angle of the seatback 36 with
respect to the seat cushion 35 reaches a predetermined target angle
as a target reclining angle before the collision occurs, as shown
in FIG. 3. The target angle may be a target angle range. That is,
the target angle may be a value within a predetermined angle
range.
When the collision determination ECU 22 determines that a collision
is imminent, the occupant protection control ECU 26 (controller)
controls a seatbelt motor 32 (seatbelt retracting part) to retract
the seatbelt 38 and thereby restrain the occupant.
As shown in FIG. 4A and FIG. 4B, the seat actuator 28 and the
seatbelt motor 32 are driven when an electric current is applied to
the seat actuator 28 and the seatbelt motor 32.
When a state change of the seat 34 is commanded by a switch or the
like (not shown), the states of the seat 34 such as a reclining
angle and a seat slide are changed by the seat actuator 28 and
another actuator respectively corresponding to the control on the
switch.
If the reclining angle of the seatback 36 exceeds the target angle
(i.e., the seatback 36 is reclined toward the rear of vehicle
beyond the target angle) and it is determined that a collision is
imminent, the reclining angle of the seatback 36 is adjusted and
the seatbelt 38 is retracted simultaneously by simultaneously
driving the seat actuator 28 to incline the seatback 36 and the
seatbelt motor 32 to retract the seatbelt 38. Accordingly, the
occupant is restrained by both the inclination of the seatback 36
and retraction of the seatbelt 38. Thus, the appropriate
restraining force of the seatbelt 38 may easily be achieved when
the occupant is restrained by the seatbelt 38.
Hence in the present embodiment, when the inclination of the
seatback 36 and the retraction of the seatbelt 38 are performed
simultaneously, the driving force of the seatbelt motor 32 when the
reclining angle of the seatback 36 is decreased (i.e., the
reclining angle of the seatback 36 is changed to the direction in
which the holding force of the seatbelt 38 increases) is set
smaller than the driving force of the seatbelt motor 32 when
retracting the seatbelt without changing the reclining angle of the
seatback 36. Specifically, in the present embodiment, the driving
force is reduced by reducing the electric current supplied to the
seatbelt motor 32. Accordingly, partial electric power for the
seatbelt motor 32 may be supplied as the electric power for the
operation of the seat actuator 28. In other words, operation of the
seatback 36 and the retracting operation of the seatbelt 38 may be
appropriately performed, and the power consumption is reduced.
In the present embodiment, the electric current that is applied to
the seatbelt motor 32 is set as a normal electric current value
when the collision determination ECU 22 determines that a collision
is imminent and the detected reclining angle of the seatback 36 is
the target angle. When the detected reclining angle of the seatback
36 is reclined beyond the target angle, the seatbelt motor 32 is
driven at an electric current lower than the normal electric
current value (i.e., the seatbelt motor 32 is driven at an electric
current is lower than the value that is applied when only the
seatbelt motor 32 is driven) as indicated by the arrow in FIG. 4B.
The magnitude of the reduced electric current is generally set to a
current value that the appropriate restraining force of seatbelt 38
is obtained when the occupant is restrained by the seatbelt 38.
In the present embodiment, adjustment of the seatback 36 when it is
determined that a collision is imminent will be described based on
the premise that the seatback 36 is reclined toward the vehicle
rear beyond the target angle. However, the present invention is not
limited to this premise. The seatback 36 may be reclined toward the
vehicle rear if the reclining angle of the seatback 36 is smaller
than the target angle (i.e., when the seatback 36 is inclined
toward the vehicle front beyond the target angle). In addition, in
the present embodiment, when the reclining angle of the seatback is
decreased (when the restraining force of the seatbelt 38 is
increased), the driving force of the seatbelt motor 32 is
controlled to be smaller than at least one of the driving force of
the seatbelt motor 32 when the seatbelt 38 is retracted without
changing the reclining angle of the seatback or when the reclining
angle of the seatback 36 is increased (when the restraining force
of the seatbelt 38 is reduced). Thus, the inclining operation of
the seatback and the retraction of the seatbelt may suitably be
performed, and the power consumption is suppressed.
Next the process executed in the ECU of the occupant protection
device 10 will be described.
First, the process performed in the collision determination ECU 22
will be described. FIG. 5 is a flow chart that shows an example of
the process that is performed in the collision determination ECU 22
of the occupant protection device 10 according to an embodiment of
the present invention. The process shown in FIG. 5 is started when
the ignition switch (not shown) is turned on and ended when the
ignition switch is turned off or when the host vehicle collides
with an object.
In step 100, the distance to an object in front of the vehicle is
input, and the process proceeds to step 102. That is, in step 100,
detected results of the front millimeter wave radar 12, the front
lateral millimeter radar 14, the stereo camera 16, etc. are
input.
In step 102, a relative speed is calculated, and the process
proceeds to step 104. For example, a relative speed is calculated
based on the distance to an object in the front detected per
certain period of time by the millimeter wave radar. A relative
speed may be calculated based on the distance obtained by image
processing of the image taken with the stereo camera 16.
In step 104, a detected result of the millimeter wave radar is
newly input, and the process proceeds to step 106.
In step 106, an estimated time of impact t, which is the estimated
amount of time before the vehicle collides with an object, is
calculated, and the process returns to step 100 and repeats the
steps described to this point. That is, the estimated time of
impact time t is calculated based on the distance to the object
detected by the front millimeter wave radar 12, the front lateral
millimeter wave radar 14, the stereo camera 16, etc. and based on
the relative speed calculated in step 102, and then the process
returns to step 100 and repeats the steps described above.
Next the process performed in the occupant protection control ECU
26 will be described. FIG. 6 is a flow chart that shows an example
of the process performed in an occupant protection control ECU 26
of the occupant protection device according to an embodiment of the
present invention. The process shown in FIG. 6 is started when the
ignition switch (not shown) is turned on.
In step 200, the estimated time of impact t calculated by the
collision determination ECU 22 is input, and the process proceeds
to step 202.
In step 202, it is determined whether the estimated time of impact
t is less than a predetermined time t1. If the determination is
affirmative, the process proceeds to step 204. If the determination
is negative, the process proceeds to step 220.
In step 204, it is determined whether the occupant protection
operation is being performed. That is, it is determined in step 204
whether driving of the seat actuator 28 and the seatbelt motor 32
has been initiated by an occupant protection device starting
process. If the determination in step 204 is negative, the process
proceeds to step 206. If the determination in step 204 is
affirmative, the process proceeds to step 208.
In step 206, the occupant protection operation process is
performed, and the process proceeds to step 216. Here, the occupant
protection operation starting process will be described. FIG. 7 is
a flow chart that shows an example of the occupant protection
operation starting process that is performed in the occupant
protection control ECU 26 of the occupant protection device 10
according to an embodiment of the present invention.
When the process proceeds to the occupant protection operation
starting process, first in step 300, a seatback angle is detected
and the process proceeds to step 302. That is, in step 300, the
reclining angle of the seatback 36 detected by the seatback angle
detection sensor 30 is obtained.
In step 302, it is determined whether or not the seatback 36 is
reclined rearward beyond the target angle. That is, it is
determined whether the detected reclining angle of seatback 36 is
larger than the target angle. If the determination is negative, the
process proceeds to step 304. If the determination is affirmative,
the process proceeds to step 306.
In step 304, the seatbelt motor 32 is driven, and then the occupant
protection operation starting process returns to the process in
FIG. 6. That is, the seatbelt 38 is retracted, and the occupant is
restrained.
On the other hand, in step 306, the seat actuator 28 are driven,
and the seatbelt motor 32 are driven at a low electric current
simultaneously, and then the occupant protection operation starting
process returns to the process in FIG. 6.
That is, in the occupant protection operation starting process, the
seat actuator 28 and the seatbelt motor 32 are driven at the same
time. The electric current applied to the seatbelt motor 32 is
changed according to whether the seatback 36 when it is determined
that a collision is imminent is reclined rearward beyond the target
angle (i.e., the electric current applied to the seatbelt motor 32
is changed according to whether the detected reclining angle is
larger than the target angle). When the seatback 36 is being
inclined forward and the retracting operation of the seatbelt 38
are performed at the same time, power consumption is reduced by
decreasing the driving force of the seatbelt motor 32.
On the other hand, in step 208 of FIG. 6, it is determined whether
the reclining angle of the seatback 36 is being adjusted. The step
208 determines whether the seat actuator 28 is being operated after
the estimated time of impact is less than the predetermined time
t1. If the determination is affirmative, the process proceeds to
step 210. If the determination is negative, the process proceeds to
step 216.
In step 210, it is determined whether the reclining angle of the
seatback 36 is the target angle (i.e., the predetermined reclining
angle). If the determination is affirmative, the process proceeds
to step 212. If the determination is negative, the process proceeds
to step 214.
In step 212, it is determined whether the prescribed period of time
elapses since the adjustment of the seatback 36 is started. In the
determination, the prescribed period of time necessary for securely
preventing the seat adjustment from continuing after a collision is
set, and whether the prescribed period of time elapses is
determined. That is, the prescribed period of time mentioned here
sets the time to stop the seat adjustment of the seatback 36 before
a collision. If the determination is affirmative, the process
proceeds to step 214. If the determination is negative, the process
proceeds to step 216.
In step 214, adjustment of the seatback 36 is stopped, or drive of
the seat actuator 28 is stopped, and then the process proceeds to
step 216.
In step 216, it is determined whether a collision occurs. Step 216
determines whether a collision is detected by a collision detection
sensor within the estimated time of impact. If the determination is
negative, the process returns to step 200 and repeats the above
steps. If the determination is affirmative, the process proceeds to
step 218 where the occupant protection device 10 is stopped and the
series of steps are terminated. Here, the stop of the occupant
protection device 10 indicates the stop of the seat actuator 28 and
the stop of the seatbelt motor 32.
In contrast, if the determination result of step 202 is negative
and the process proceeds to step 220, it is determined whether the
occupant protection operation is being performed. That is, step 220
determines whether the seat actuator 28 and the seatbelt motor 32
are being driven after starting of the occupant protection device
starting process. If the determination is affirmative, the process
proceeds to step 222. If the determination is negative, the process
returns to step 200 and repeats the above steps.
In step 222, the seat actuator 28 and the seatbelt motor 32 that
are being driven are reset and stopped, and then the process
returns to step 200 and repeats the above steps. When the seat
actuator 28 is being driven, the seat actuator 28 may be driven so
as to return the reclining angle of the seatback 36 to the
reclining angle of the seatback before the driving of the seat
actuator began (initial reclining angle).
As described above, if it is determined that a collision is
imminent (when the estimated time of impact becomes less than the
predetermined time t1) the occupant protection device 10 according
to the embodiment of the present invention adjusts the reclining
angle of the seatback 36 to the target angle, and adjusts the
position of the occupant to the suitable state. Therefore, occupant
protection may suitably be performed by the seatbelt 38 and an air
bag and the like. At the same time, the protection of the occupant
may be secured by retracting the seatbelt 38 and restraining the
occupant.
If it is determined that a collision will occur, the occupant
protection device 10 reduces the electric current supplied to the
seatbelt motor 32 to be lower than the electric current supplied to
the seatbelt motor 32 when the seatback 36 is the target angle and
the seatbelt motor 32 alone is driven. Thus, the inclination of the
seatback 36 and the retracting operation of the seatbelt 38 can
suitably be operated, and the power consumption is suppressed.
Next, a modification of the occupant protection device according to
the embodiment of the present invention will be described.
In the above embodiment, when it is determined that a collision is
imminent, the occupant protection device 10 reduces the electric
current supplied to the seatbelt motor 32 to be lower than the
electric current supplied to the seatbelt motor 32 when the
seatback 36 is the target angle and the seatbelt motor 32 alone is
driven. However, in the modified embodiment, when the seatback 36
is reclined vehicle rearward beyond the threshold reclining angle,
retraction of the seatbelt 38 is prohibited in order to maintain a
sufficient amount of electric power to drive the seat actuator 28
for seatback 36. The difference between these embodiments lies in
the starting process of the occupant protection operation, and thus
only the difference will be described.
FIG. 8 is a flow chart that shows a modification of the occupant
protection operation start process performed in the occupant
protection control ECU of the occupant protection device according
to an embodiment of the present invention. The same processes as in
FIG. 7 are denoted by the same symbols.
When the process proceeds to the occupant protection operation
starting process, first in step 300, a seatback angle is detected
and the process proceeds to step 302. That is, in step 300, a
reclining angle of the seatback 36 detected by the seatback angle
detection sensor 30 is obtained.
In step 302, it is determined whether the seatback 36 is reclined
rearward beyond the target angle. That is, it is determined whether
the detected reclining angle of seatback 36 exceeds the target
angle. If the determination is negative, the process proceeds to
step 304. If the determination is affirmative, the process proceeds
to step 305.
In step 304, the seatbelt motor 32 is driven, and then the occupant
protection operation starting process returns to the process in
FIG. 6. That is, the seatbelt 38 is retracted, and the occupant is
restrained.
In step 305, it is determined whether the detected reclining angle
of the seatback 36 exceeds the threshold angle (threshold reclining
angle). If the determination is negative, the process proceeds to
step 306. If the determination is affirmative, the process proceeds
to step 308.
In step 306, the seat actuator 28 are driven, and the seatbelt
motor 32 are driven at a low electric current, and then the
occupant protection operation starting process returns to the
process in FIG. 6.
In step 308, the seat actuator 28 alone is driven, and then the
occupant protection operation starting process returns to the
process in FIG. 6. That is, only adjustment of the seatback
reclining angle is permitted and only the seatback reclining angle
is adjusted with the retraction of the seatbelt 38 prohibited.
In the same way as the preceding embodiment described above, in the
modification of the occupant protection operation starting process,
if it is determined that a collision is imminent, the occupant
protection device 10 reduces the electric current supplied to the
seatbelt motor 32 to be lower than the electric current supplied to
the seatbelt motor 32 when the seatback 36 is the target angle and
the seatbelt motor 32 alone is driven. Thus, the inclination of the
seatback 36 and the retracting operation of the seatbelt 38 can
suitably be operated, and the power consumption is suppressed.
In the modified embodiment, when the seatback 36 is tilted beyond
the threshold angle, that is when the seatback is reclined at an
extreme angle, the seatback 36 alone is driven while the retraction
of the seatbelt 38 is prohibited. Thus, the electric power
necessary for driving the seatback 36 can be maintained
sufficiently. While only the seatback actuator 28 from among the
seatbelt motor 32 and the seatback actuator 28 is driven so as to
decrease the reclining angle of the seatback 36 (i.e., while the
retraction of the seatbelt 38 is prohibited in step 308), if it is
determined that the estimated time of impact t is less than a
predetermined time t2 that is smaller than the predetermined time
t1 of step 202 (i.e., when the collision is very imminent), the
occupant protection control ECU 26 may control to stop the seatback
actuator 28 and to permit the retraction of the seat belt 38 so
that the seatbelt motor 32 starts the retraction of the seatbelt
38. It is preferable that the seatback 36 is inclined frontward
even a little when the rear collision is imminent. However, if it
is determined that the frontward inclination of the seatback 36
occurs no effect when the frontal collision is imminent, the
inclination of the seatback 36 may be completely prohibited.
In the embodiment described above, the seat actuator 28 is driven
to incline the seatback 36 only when the reclining angle of the
seatback 36 exceeds the target angle (when the seatback 36 is
reclined vehicle rearward beyond the target angle) and it is
determined that a collision is imminent. However, the present
invention is not limited to this. For example, the seat actuator 28
may be driven to recline the seatback 36 toward the rear of the
vehicle when the reclining angle of the seatback 36 is below the
target angle (when the seatback is inclined beyond the target
angle). In this case, the seatback 36 moves in the direction in
which restraining force of the seatbelt 38 decreases. Hence the
restraining force of the seatbelt 38 may be increased by increasing
the driving force of the seatbelt motor 32 by, for example,
increasing the electric current supplied to the seatbelt motor 32
above the amount of electric current supplied when the reclining
angle of the seatback 36 is the target angle and the seat actuator
28 need not be driven (or larger than the electric current that is
supplied when the reclining angle of the seatback 36 is larger than
the target angle and the seat actuator 28 is driven to incline the
seatback 36). The seatback is easily reclined rearward due to the
occupant's weight applied thereon. Hence when the seatback 36 is
reclined rearward, the driving force of the seat actuator 28 may be
set lower than the driving force that is applied when the seatback
36 is inclined forward in order to reduce power consumption.
In the above embodiment, the case where the seatbelt motor 32 is
stopped when the seatbelt 38 is retracted by the seatbelt motor 32
after predicting of the collision has not been specifically
described. However, the seatbelt motor 32 may stop if the load of
retracting the seatbelt 38 reaches a predetermined level, or may be
stopped if the estimated time to collision passes or when the
collision occurs, or may be stopped when a prescribed period of
time elapses since the time the seatbelt motor 32 began
operation.
In the above embodiment, monitoring of the front and rear is
performed by the front millimeter wave radar 12, the front lateral
millimeter wave radar 14, the stereo camera 16, the rear millimeter
wave radar 18, and the rear lateral millimeter wave radar 20.
However, the present invention is not limited to this. The
monitoring may be performed by a detection part such as a radar
that monitors the side of the vehicle. The occupant protection
control ECU 26 may change the reclining angle of the seatback 36
based on the collision configuration.
The present invention is not limited to any of the above
embodiments, and the above embodiments may be modified within the
scope of the present invention.
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